It has been suggested that glenoid component retroversion and eccentric loading are an important mechanism leading to glenoid component loosening, but little clinical data have been published to support this concept.Methods:
Sixty-six shoulders underwent total shoulder replacement with an all-polyethylene press-fit pegged glenoid component designed for osseous ingrowth for treatment of osteoarthritis. These shoulders were followed clinically and with radiographs for an average (and standard deviation) of 3.8 ± 1.8 years (range, two to seven years). Preclinical radiographic loosening was defined as osteolysis around the central peg of the glenoid component.Results:
Of the sixty-six shoulders, twenty (30%) had osteolysis around the center peg. The length of time after replacement (p = 0.0006), preoperative glenoid retroversion (p = 0.036), and postoperative glenoid component retroversion (p = 0.041) were correlated with osteolysis around the glenoid center peg and an increase in the Lazarus component loosening grade. Postoperative retroversion correlated with preoperative retroversion (Pearson correlation coefficient = 0.44, 95% confidence interval [CI] = 0.19 to 0.64, p = 0.0011). The presence of osteolysis around the center peg was not correlated with a worse clinical outcome defined by shoulder scores or a reoperation due to glenoid loosening. After adjustment for follow-up time, excessive postoperative glenoid retroversion (≥15°) was associated with an increased odds of osteolysis (odds ratio = 5.23, 95% CI = 1.31 to 20.9]), whereas preoperative glenoid retroversion was associated with no change in the odds of osteolysis.Conclusions:
Osteolysis around the center peg of a glenoid component is correlated with component retroversion of ≥15°. This finding suggests that there should be additional investigation into the effects of correcting preoperative glenoid retroversion to prevent osteolysis around the center peg.Level of Evidence:
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.